Carbon nanotubes (hereinafter “CNTs”) have highly accessible surfaces, low resistivity, and are highly stable. Due to their special geometry and unique electronic, mechanical, chemical and thermal properties, CNTs have been used in various applications. For example, CNTs can be combined with polymers to produce different nanocomposites. In the past decade, various polymers, such as hyperbranched polymers, polycaprolactone (C6H10O2), polystyrene ((C8H8)n), polyacrylates, and polyurea, have been combined with CNTs to produce nanocomposites.
Fixation is a process for stabilization of biological tissues. To stabilize biological tissue, decomposition caused by tissue enzymes and decay must be prevented and the tissue should be hardened for convenient handling. Generally, two approaches have been used to fixate biological tissue. The first approach is physical and involves the rapid heating or freezing of tissue. The second approach is chemical and involves applying organic fixatives, such as tannic acid (C76H52O46), picric acid (C6H3N3O7), and absolute alcohol, or inorganic fixatives, such as potassium dichromate (K2Cr2O7), mercuric chloride (HgCl2), and osmium tetroxide (OsO4), to biological tissue.
One common fixative, osmium tetroxide, stabilizes many proteins by transforming them into gels without destroying their structural features. In addition, tissue proteins that are stabilized by osmium tetroxide are not coagulated by alcohols during dehydration. Osmium tetroxide can also be used as a lipid staining agent in scanning electron microscopy, transmission electron microscopy, and optical microscopy.